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A network device isn't listed in System Preferences Sound pane or Audio MIDI Setup


Assuming the computers are running, have Shairwaves installed, and are reachable over the network, Shairwaves network devices need three conditions to be present to be listed as an audio device.
  • It must be on a computer on the same switched network as the host computer
  • It must be set to be shared by the host computer
  • It must be set to be in use in the Remote devices tab on the client computer
  • It must not be already be being played to by another computer (including the host computer) unless shared using a fixed format
Check that the device has been set to be shared. If it has then it will be shown in the Network devices tab of the Shairwaves preference pane on each computer. Then check that the device has been set to be in use on the computer in question, again this is shown in the Network devices tab. Now check whether another client is already playing to the device - it will be shown in red in the preference pane, and will have a strikethrough line through it. If it is red then hover the mouse pointer over the device name to bring up a tooltip to show which computer is using it (make sure tooltips are enabled).

It may be that the device is being shared with a name which is different to the default one, check on the host computer to see the name the device is being shared with.

If it is shared, set to be in use and not being played to by another computer, and still no device is listed in the System Preferences Sound pane, with the computer running, Shairwaves installed and the computer reachable over the network, check to see whether other sharing services are available, e.g. file sharing. If they are, please contact the support address for help. If not then there may be a wider issue which may be cured by rebooting the computers or resetting the networking equipment.

If Shairwaves is being used in evaluation mode, i.e. prior to purchase, then it is likely that the evaluation time period has expired. It can be reset by rebooting your Mac.



The devices shared by a Mac aren't listed on the others at all

If the above conditions have been met, this is likely to be caused by the Mac OS firewall. If the firewall is enabled, make sure the "Automatically allow signed software to receive incoming connections" option is enabled.


I have a device which is shown as being played to but no application is playing to it

Some audio applications play silence to a device when playback is stopped, rather than stopping playing audio to it. It can be hard to discover which application is doing this and the only sure way is to quit each suspect one in turn until the device goes idle.

With built-in devices on older Macs, and also with some USB devices, the audio input and output sides are sometimes treated as being part of one device. The whole device is considered to be active even if just one of those sides is active. This means that if you have an application recording from the device's input side, it will not be available for other computers on your network to play to it even if the output side is not being used.



There are frequent gaps in the audio output


Shairwaves is reliant on timely delivery of audio over the network, and if this doesn't happen there may be gaps in the audio output.

If the gaps occur quickly and regularly, say five times a second for two seconds, with reception being fine for a while between this happening, then this is caused by the Mac performing Wifi scans. Scans disable transmission for short periods several times a second, meaning that gaps will be heard if low latency settings are used. The minimum latency setting needed to avoid this problem is approximately 250ms. Alternatively it is necessary to discover which Mac service or application is causing the scans and to disable it. Shairwaves does not initiate Wifi scans. The problem does not occur when using wired networking.

Otherwise it is likely to be caused by problems with network transmission.

Choosing a higher latency allows the computer sharing the device to have more audio to play to it when there are network delays. This helps in reducing the gaps but increases the delay between the applications playing audio and the audio being heard. This means that the audio heard will follow behind actions such as clicking through a track in iTunes.

If the Wifi signal is at the limits of reception then increasing the latency value is likely to worsen performance. In this situation the only solution is to improve reception or use wired networking.

Shairwaves uses network features to provide reliable audio transmission by using prioritised packets designed for applications needing reliable real-time data delivery. On Wifi it uses Wifi Multimedia (WMM). On a base station where this feature is enabled, Shairwaves packets will not be delayed no matter how busy the network is for other traffic, such as large file transfers. For networking hardware which does not implement this feature optimally, or at all, or where it is switched off, Shairwaves audio will get through but may suffer gaps in output at times of high network usage, even at high latency settings.


When I change the name of a device or data source in the Local devices tab, the names remain in the same in the System Preferences Sound pane and in Audio MIDI Setup

This is normal, changing these names only affects the names used to share the device with other computers, the name of the device on the local computer does not change.

However changing the names of devices in the Network devices tab does change the names shown in the Sound pane and Audio MIDI Setup. Some applications which let you choose an output device from their own list of audio devices, separately to the Sound pane, do not update their list dynamically and may need to be restarted to reflect these changes.



iTunes can play 5.1-channel AC3 soundtracks in downloaded movies, can it also import and play 5.1-surround music?

5.1-channel surround AC3 audio files can be imported into iTunes and played, with iTunes automatically handling the setting up of the output device for encoded audio, just as with iTunes movies. However it is necessary to place the audio in a MP4 container in a ".m4v" file, similar to a podcast file. This process is not especially automatic and third party applications are needed with some technical awareness on how to use them. However given that, as a guide the following have been found to be needed for successful importing and playback:
  • there must be two audio streams in the MP4 container, the first being a conventional stereo one, e.g. AAC-encoded as with many podcasts
  • the raw AC3 stream is multiplexed as the second stream
  • it is possible to add album and chapter metadata to the stream, with tracks being accessed from an additional Chapters menu in iTunes
  • at present it is necessary to select the AC3 track each time when first playing the album, as with iTunes movies
The first audio track should be the same duration as the AC3 audio, but can contain silence with a low encoding rate to save space if only the AC3 audio is needed.

With that, the ".m4v" files can be added to your iTunes library just like any other tracks, and played in the same way but now with great 5.1 surround sound over your network direct from your Mac.

DTS surround audio, another popular surround audio format, has not been witnessed working succesfully.


The preference pane tooltips disappear too quickly

Shairwaves tooltips operate slightly differently to standard Mac OS tooltips. To stop the tooltip disappearing, move the mouse pointer onto it. When you have finished move it away or click on the tooltop to make it disappear immediately.


I reconnected a USB or HDMI device and all the settings have been lost, both on the sharing computer and the clients

Shairwaves stores the settings for all audio devices you connect to your Mac, such as whether or not it has been set to be shared. If you share the device with other computers then all their settings for it, such as the chosen name and whether or not to use it on their computer, are also stored as are the device sample rate, number of channels etc.. This is because each device type has its own identity which allows it to be recognised and the previous settings to be restored when it is reconnected (if it is set to be shared, you are warned when the device is reconnected).

USB and HDMI devices are identified not just by their type but also where they are connected. For example if you connect a USB device to a USB port on your Mac then move it to a different port, it will be treated as a different device. So to maintain the settings, make sure you use the same port. The same applies to connecting the device via a hub - each hub port is also separately identifiable.

Sometimes this is a useful feature. If you have multiple devices of the same type connected to the same computer, when playing to one of them you can rely on the audio always coming out of the same device, as long as you can tell which it is by giving it a custom name.

On Macs with HDMI interfaces, including HDMI adaptors connected via your Mac's DisplayPort or Thunderbolt port, each type of HDMI audio hardware connected to the Mac is treated as a different device and needs to be configured separately. This is not the case with the Raspberry Pi HDMI interface, which is treated as the same device no matter which equipment is connected.



I have a device which doesn't work properly with Shairwaves (in some way)

Please check how the device works when used in the same way on the sharing computer, i.e. not involving Shairwaves. If it behaves in the same way then the problem is likely to be the device or an incompatibility between it and OS X. If the device works fine when used locally but not when used via Shairwaves, please contact the support address for help.


I have a Raspberry Pi running the Shairwaves server, but cannot see the built-in device's HDMI port on the other computers

The HDMI port is not shown as part of the device (as one of its data sources) until HDMI equipment is connected to it. Additionally, if you have an HDMI switch between the Raspberry Pi and the audio hardware, then the remote representation of the Raspberry Pi's HDMI port will not appear unless the Raspberry Pi is selected on the switch.


I have a Raspberry Pi running the Shairwaves server, but cannot get DVD Player or iTunes to play encoded audio to it even though the HDMI port is connected to hardware which supports encoded audio

DVD Player and iTunes, along with other audio applications, do not provide facilities for devices which have multiple user-selectable data sources. For Raspberry Pi devices, encoded audio formats will only be visible if the HDMI data source is selected, the 3.5mm output does not support these formats. It may be necessary to restart the application once this has happened, the selection being achieved via the Shairwaves preference pane, the Sound preference pane, or in Audio MIDI Setup. It should then be possible to select the device as a digital output for encoded 5.1 audio.

The same applies to other devices with selectable data sources.


What are the Linux "plug-and-play" installation network requirements?

The Linux "plug-and-play" SD card / memory stick downloads assume the network provides IP addresses by DHCP over Ethernet. The model A Raspberry Pi has no built-in network adaptor and it is necessary for an external Ethernet adaptor to be connected when power is applied.

It is possible to add a Wifi adaptor to the Raspberry Pi but it is necessary to ensure that a particular adaptor is supported. The Shairwaves "adsdconfig" utility provides an option for configuring the interface using the Linux "wifi-menu" tool.



I have a device which has the 'use' box checked and is listed as an available device, but it is not possible to select it as the default output

If the device is in use for playback of encoded audio formats, e.g. Dolby Digital and DTS, then it is not possible to select it as the default output. Sometimes applications leave the device in this state when they are no longer using it and have quit. To correct this, select the device in the Audio MIDI Setup application and set the output format to a setting other than 'Encoded Digital Audio'. This will allow the device to be selected as the default output.







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